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2. What is a computer ? A computer is an electronic device which performed arithmetic and logical operations. It can also store a large volume of information. 2

3. How does a computer work? INPUT  PROCESS  OUTPUT DATAINSTRUCTION. INPUT consists of DATA & INSTRUCTION. PROCESS is a set of instructions stored in the computer to carry out the instructions given by the user. The process is also called a PROGRAM. OUTPUT is the set of results generated after processing the Input. 3

4. HARDWARE Hardware are the PHYSICAL COMPONENTS of the Computer System. Examples : Mother Board Processor RAM HDD SMPS CD/DVD-ROM 4

5. SOFTWARE Software are the logical components of the computer system. These are basically the programs and information stored in the computer. Examples: MS-Office Photoshop Auto-CAD 5

6. INPUT DEVICE It is used for transferring data from the users end to the computer. OUTPUT DEVICE It is used to transfer processed information from the computer to the user in a way required by the user. 6

7. MEMORY UNIT It stores instruction and data and provides them to the various other units as and when required. It is basically the working memory of the computer system. This memory unit is volatile, i.e. it is temporary memory and nothing can be stored here permanently. The information is stored in the main memory as long the computer is switched on or as long as it is required by the computer. 7

8. CONTROL UNIT Controls the various operations within a computer. It basically manages all the other units and devices of the computer system. It does so by transmitting timing and control signals to the various devices and units. 8

9. ARITHMETIC & LOGIC UNIT It performs the various arithmetic and logical operations on the data stored in memory, as dictated by the instruction. There are various basic circuits to perform these operations. 9

10. BLOCK DIAGRAM MEMORY UNIT INPUT DEVICE CONTROL UNIT ARITHMETIC & LOGIC UNIT OUTPUT DEVICE SECONDARY STORAGE CONTROL FLOW DATA FLOW CPU 10

11. Input devices : KEYBOARD : It is an input device to give character based inputs to the computer. All types of data, instruction and information can be given through the keyboard. It is an input device to give character based inputs to the computer. All types of data, instruction and information can be given through the keyboard.HARDWARE 11

12. MOUSE : It is used for graphics based inputs. It can mainly select some graphical icons and select some options from a menu. It can not be used for giving data to the computer. 12

13. SCANNER : It is used for graphical inputs. Pictures, images, drawings etc. can be scanned and stored in the computer. 13

14. OUTPUT DEVICES VDU : Visual Display Unit. Also called a monitor or a screen. It a device similar to a TV screen. The output on a VDU is temporary. 14

15. PRINTER : A printer produces output on paper which can be permanently kept. TYPES OF PRINTERS : Inkjet Printer Laser Printer Dot Matrix Printer[DMP] 15

16. PLOTTER : It is a special kind of printer for printing drawings on large sheets of paper. 16

17. STORAGE DEVICES HARD DISK : It a device fixed to a computer and can store large volumes of information. It uses magnetic media and electro magnetic theory to read and store information. 17

18. FLOPPY DISK : It is a cassette like device to store information. It is external to a computer and can be put into a floppy disk drive (FDD) attached to a computer for reading and writing information. It also uses electro magnetic theory. Standard capacity : 1.44 MB 18

19. CD : It stands for COMPACT DISK. It is the same as any other music or video CD. It is also external to a computer and can be put into a CD drive attached to a computer for reading information. It uses OPTICAL technology to read information. Standard capacity : 650 MB 19

20. MEMORY : There are two types of memory : RAM & ROM. RAM : Random Access Memory. It is the main memory of the computer. It is volatile memory and the information gets erased whenever the power supply is switched off. 20

21. ROM : Read Only Memory Information is burnt into the ROM chip at the time of manufacturing. It can not be erased or altered and fresh information can not be written into the ROM. The BIOS is stored on ROM because the user cannot disrupt the information. BIOS : Basic Input Output System. It contains some instructions required internally by the computer. 21

22. CPU : Central Processing Unit. It is also called the micro processor. There are CPUs with varying efficiency and the quality of the computer depends mainly on the CPU present on the main board. 22

23. MOTHER BOARD : The main circuit board housing the microprocessor, RAM, ROM and connecting interfaces to the various other devices and peripherals. 23

24. OPERATING SYSTEM : Programs to control the hardware and provide user interface. It is essential for every computer. Functions : Memory managementMemory management CPU managementCPU management Input / Output managementInput / Output management Storage / File managementStorage / File management Provide user interfaceProvide user interface 24

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26. Information technology can be used: To help solve crime. In the supermarket. In the music industry. In the TV and video industry. In medicine. In banking. To control traffic. To monitor pollution. In education. 26

27. To help solve crime the police use: The Police National Computer (PNC) keeps computerised records (sorted into indexes) of stolen and suspect vehicles, vehicle owners, the names of convicted, wanted, or missing people, the names of disqualified drivers, fingerprints, and DNA obtained from people who have convicted of a crime. Databases to handle information gathered during major investigations. 3D modelling programs to recreate crimes. Centrally controlled and monitored CC TV Security cameras. 27

28. Supermarkets use computers. To scan the barcodes on products that are sold. To scan the barcodes on products as they are delivered To add up customers bills and to charge them for what they have bought. To order new stocks from suppliers To keep all their stores and warehouses fully informed about new products, changes in company policy, and other information (using email). 28

29. The music industry uses computers: To digitally record music. To produce electronic music using synthesisers. To ‘sample’ existing recordings. To speed up the production of new recordings (it is much easier to record each element of a recording separately and then blend them together than trying to do it all at the same time). 29

30. In medicine computers are used: To keep patients’ records up-to-date. To monitor patients who are in intensive care. To produce images or scans of parts of the body (e.g. ultra-sound scans of the womb for pregnant mothers, PET [Positron Emission Tomography] scans to detect cancer, CAT [Computerised Axial Tomography) scans that produces a 3D image of the inside of a patient’s body). 30

31. Banks use computers: For MICR (Magnetic Ink Character Recognition). For EFTPOS (Electronic Fund Transfer at Point Of Sale). For EDI (Electronic Data Interchange). To administer the credit and debit card systems. To combat credit and debit card crime. For clearing cheques via the BACS (Bankers’ Automated Clearing Service). To run their network of ATMs (Automatic Teller Machines) 31

32. Traffic management uses computers: To control traffic lights to maintain an even flow of traffic. To manage parking by directing traffic towards empty car parks. To control speed monitoring cameras in accident hotspots. To control speed limits and traffic flow on motorways via the system of road-side matrix signs. 32

33. Computers can be used to monitor pollution: Using remote sensing stations connected to a central monitoring computer via the Internet. To predict changes in pollution levels by using modelling based on existing data. 33

34. In education computers are used: For interactive learning (e.g. using whiteboards, self-marking tests, educational games). For distance learning (where pupils can access learning programs and/or information from home via the Internet). For administration (e.g. examination entries, reports, attendance). 34

35. Book  Intro To IT  Programming In C Language  Fundamental of computer Teacher’s Notes Friends Internet 35

36. The End Presented by Bimal Dhakal 36